Microsurgical Rat Varicocele Model

Abstract

A rat varicocele model using partial occlusion of the left renal vein was described previously. Reproducibility in creating this model has met with varied success. Alternate routes of testicular venous drainage may negate the effect of partial renal vein occlusion on varicocele creation. We hypothesized that varicocele induction would be more effective if microsurgical ligation of the gonadal venous drainage to the common iliac vein was combined with partial occlusion of the left renal vein. We randomly assigned a total of 36 rats to 3 groups, including sham surgery, partial renal vein occlusion alone (the classic technique) and microsurgical ligation. Half of the rats in each group were evaluated at 5 and 12 weeks, respectively. We evaluated internal gonadal vein and spermatic cord diameter, testicular weight, cauda epididymal sperm concentration and motility and testicular histology using the Johnsen score as well as serum and intratesticular testosterone and dihydrotestosterone. Five weeks after varicocele creation the microsurgical ligation group had a larger spermatic cord diameter and lower Johnsen scores than rats in the classic technique and sham surgery groups. At 12 weeks the microsurgical ligation group had a larger spermatic cord diameter, lower cauda epididymal sperm concentration, lower sperm motility and worse histology than the classic technique and sham surgery groups. There was no difference in serum androgen outcomes but the microsurgical ligation group had lower intratesticular androgens. Adding microsurgical ligation of testicular vein collaterals in the pelvis to partial renal vein occlusion appears to improve the effectiveness of creating a rat varicocele model.